A variety of information/signal processing apparatuses including a network equipment instanced by a router, a server, and a large-sized computer, large-scaling and acceleration of information/signal processing are in an active phase. In these apparatuses, signal transmissions between a CPU (Central Processing Unit) and a memory on a circuit board, between wiring boards and between devices (racks) have hitherto been conducted via electric wiring. However, a so-called optical interconnection launches into actual introduction, in which the signals are transmitted optically by using optical fibres replacing the electric wiring as transmission paths owing to superiority in terms of a transmission speed, a transmission capacity, power consumption, radiation from the transmission path, and interference of electromagnetic waves with the transmission path.
Such an optical interconnection involves using, as main optical components, an optical transmission module including a light emitting element of converting electric signals into optical signals and transmitting the optical signal, and an optical reception module including a light receiving element of receiving and converting the optical signals into the electric signals, or an optical transmission/reception module having both of functions. These modules are generically termed optical modules.
Large-capacity communications are enabled by transmitting the optical signals in parallel between the optical modules via a transmission channel. In many cases, the optical fibres are used as the transmission channel for transmitting and receiving the optical signals between the optical modules. Hence, generally an optical coupling device is employed for optical coupling between the optical fibre and the optical module.
Incidentally, the optical fibre has basically flexibility and is therefore allowed to be bent and slackened to some degree. The general optical fibre is, however, prescribed in minimum diameter of an allowable flexure for ensuring transmission efficiency of light. Accordingly, a restriction of an installation space requires a flexure equal to or smaller than the minimum diameter, in which case there is used an optical coupling device configured to conduct the optical coupling by cutting the optical fibre and bending an optical path of light beams transmitted between the cut optical fibres. The use of this optical coupling device leads efficient reception on the whole and enhances the optical transmission efficiency as the case may be. A merit of the optical coupling device may likewise occur also in the optical coupling between the light emitting element and the optical fibre or between the optical fibre and the light receiving element without being limited to between the optical fibres. Herein, the light emitting element, the light receiving element and the optical fibre are generically termed optical elements.
For performing the optical coupling between the optical elements, the optical coupling device involves using an optical connector having a structure to bend the optical path in some cases. A PT (Photonic Turn) optical connector (standardized by JPCA-PE03-01-06S) configured to deflect an optical axis through 90° within the connector is utilized as the optical connector such as this.
The PT optical connector is a board packaging type optical connector for optically coupling a multicore optical fibre instanced by a multicore fibre tape core wire to the optical element on a flexible wiring board. Patent Document 1 describes an optical path change element, applicable to the PT optical connector, to bend the optical path of the multicore fibre.